Ministry of Higher Education
The High Institute of Engineering and Technology in Mansoura
Electronics & Communications Engineering Department

Name
Section
ID

Experiment No.
1
2
3
4
5
6
Total Marks
Date Marks Signature

Week 1
Week 2
Week 3
Week 4
Week 5
Week 6
Week 7
Week 8
Week 9
Introduction to Electric Lab
Experiment No.(1) Verifying Ohm's Law
Experiment No.(2)
Experiment No.(3)
Resistance Connected in Series and in Parallel
Measuring the self-inductance of a coil
Experiment No.(4)
Experiment No.(5)
Experiment No.(6)
Experiment No.(7)
Experiment No.(8)
Experiment No.(9)
Measuring the capacitance of a capacitor
Kirchhoff’s Voltage and Current
Laws
Verifying the Principle of
Superposition
Verifying the Reciprocity Theorem
Verifying Thevenin's Theorem
Verifying Norton's Theorem
36
38
40
42
45
31
34
4
24
27

1. You must not damage or tamper with the equipment or leads.
2. You should inspect laboratory equipment for visible damage before using it. If there is a problem with a piece of equipment report it to the technician or lecturer. DO NOT return faulty equipment to a storage area.
3. You should not work on circuits where the supply voltage exceeds 40 volts without very specific approval from your lab supervisor. If you need to work on such circuits, you should contact your supervisor for approval and instruction on how to do this safely before commencing the work.
4. Always use an appropriate stand for holding your soldering iron.
5. Turn off your soldering iron if it is unlikely to be used for more than 10 minutes.
6. Never leave a hot soldering iron unattended.
7. Never touch a soldering iron element or bit unless the iron has been disconnected from the mains and has had adequate time to cool down.
8. Never strip insulation from a wire with your teeth or a knife, always use an appropriate wire stripping tool.
9. Shield wire with your hands when cutting it with a pliers to prevent bits of wire flying about the bench.
2

Symbol
3
Safety and Common Symbols
Description
Protective conductor terminal
Direct current
Alternating current
Both direct and alternating current
Three-phase alternating current
Earth (ground) terminal
On (supply)
Off (supply)

Introduction to Electric Lab
Purpose:

To become familiar with simple electric measurements and test equipment including the voltmeter, ammeter, and ohmmeter.

To become aware of measurement techniques including voltage across and current through electric components. Measuring electronic parameters as a function of time through oscilloscope measurements, understanding scope displays and how to focus them on areas of interest.

To become familiar with electrical passive components and how to connect them in different electrical circuits
Passive Components
The basic passive electrical components include resistors, capacitors, and inductors. The term ‘passive’ describes circuit elements which do not add energy to a circuit. Resistors dissipate energy (convert electrical energy to heat), while capacitors and inductors store it
You have to understand how to differentiate, read (know their values) and to connect different passive components.
Lab Equipment

DC Power Supply

Variac (variable AC source)

AC and DC Ammeters

AC and DC Voltmeters

Oscilloscope

Multimeter
4

.
Function Generator تاجوملا دلوم : لاوأ
: لولأا عونلا
10MHz Portable Function Generator (MFG-3010)
1. 0.1Hz
10MHz frequency
2. Output waveform: Sine, triangle, square, ramp, pulse
3. Voltage control frequency capability
1.Frequency of models:0.1Hz
2MHz/5Mhz/10Mhz/13Mhz/15MHz
2.Output waveform :sine, Triangle, square, ±Ramp, ±Pulse
3.Voltage control frequency (VCF) capability
4.TTL/CMOS and output synchronous output
5.Less than 1% distortion at 10Hz 100Khz
6.Less than 0.5dB frequency response at 0.1Hz
100Khz,1Hz 30MHz frequency counter
7.1Hz~30MHz frequency cou nter
8.AM/FM function optional (model with suffix "A" include this function)
9.FM/Sweep function optional(model with suffix "C" include this function)
تافصاوملا
تازيمملا
5

6

SG1638N Function Generator Front Panel
SG1638N Function Generator Back Panel
7
: ىناثلا عونلا
SG1638N Function Generator / Counter

(1)Power
(2) LED window: this window indicates the frequency of output signal, when “EXT” is on, it displays frequency of external signal. If over the measurement range, the light
“overflow” is on.
(3) Frequency: adjust this rotary to change output frequency signal, the frequency will be big while turn it clockwise.
(4) Wave form: choose the wave you need if you press the correspondence key.
(5) ATTE: The voltage output attenuate switch, two-switch combination is 20db, 40db,
60db.
(6) Frequency range selector: (frequency counter gate switch): Press one key according the needed frequency.
(7) Counter/Frequency terminal: Counter, EXT frequency input terminal.
(8) EXT frequency switch: Press this switch, LED window will display EXT signal frequency or counter value.
(9) Level adjustment: Press level adjustment switch, the light “level” is on, then adjusting level adjustment rotary can change DC level offset.
(10) Amplitude: The voltage output amplitude will be big while turning it clockwise, and the value will be small while turning it counterclockwise.
(11) Voltage out: voltage is out via this terminal.
(12) TTL/CMOS out: TTL/CMOS is out via this terminal.
(13) VCF: Voltage controlling frequency change input is via this terminal.
(14) SYMMETRY: sym switch, duty adjustable rotary, press duty switch, the light “SYM” is on; adjusting duty rotary can change the duty of wave.
(15) 50Hz sine output: 50Hz about 2Vp-p sine wave deliver via this terminal.
(16) Press the switch: 50Hz sine out
(17) Single sine output
(18) Press the switch: single sine output
(19) 110V/220V voltage selector
(20) AC 220V input socket.
8

: ثلاثلا عونلا
SG1642C Function Generator / Counter
1.Multi waveform:Sine,Triangle,Square,Ramp,Pulse,TTL and CMOS
2.Various output mode CW,Function,INT/EXT Sweep,AM,FM,FSK,Power,Single
3. DC Offset, Symmetry, Amplitude continuously adjustable
4. Built-in counter with INT (5digits)/EXT (8digits) up to 100MHz/equal accurate
5. High reliability MTBF>10000h
6. Full output protection
7. Output amplitude display peak-peak and RMS
8. Interface option RS-232 or RS-485
تازيمملا
9

10

M21-7000 DIGITAL TRAINING SYSTEM
: ايناث
11

(1)POWER SWITCH / POWER INDICATOR
(2)VARIABLE POSITIVE POWER
(3) VARIABLE NEGATIVE POWER
(4)POTENTIOMETERS (VR1=1k , VR2=100k )
(5)FREQUENCY VARIABLE
(6)WAVEFORM AMPLITUDE VARIABLE
(7)WAVEFORM SELECTORS
(8)FREQUENCY RANGE
(9)16 BITS DATA SWITCHES
(10)16 BITS LED DISPLAYS
(11)DIGITAL DISPLAYS
(12)REMOVABLE BREADBOARD
(13)ADAPTER
(14)TWO PULSE SWITCHES
(15)SPEAKER
(16)UNIVERSAL CONNECTOR FIXED HOLDERS
12

: اثلاث
UTD 2062C 60MHz 500MS/s Digital Storage Oscilloscope
13

Specifications
14

: اعبار
Adjustable DC Power Supply RXN-305D
- 30V 5A
Main Features
- Single channel output
- Front/ behind output terminal
- Internal radiator and electronic temperature control cooling
- Digital or pointer meter display output voltage and output current
- Current-limiting protection and users can set the current-liming protection point arbitrarily
- Reverse polarity protection
Specifications
- Voltage Output: 0-30V (Adjustable)
- Current Output: 0-5A (Adjustable)
- Input voltage: AC 220V±10% 50Hz/60Hz (also can be AC 110V±10% 50Hz/60Hz if required)
- Working Condition Temperature: -10-40Degrees Celsius Relative humidity: 90%
15

- Storage Condition Temperature: -10-40Degrees Celsius Relative humidity: 80%
- Constant Voltage Operation Voltage stability : ≤0.01%+2mV
- Load stability : ≤0.01%+2mV
- Recovery time : ≤100uS - Ripple and noise: ≤1mVrms ( effective value )
- Temperature coefficient : ≤200PPM/Degrees Celsius
- Constant Current Operation Current stability : ≤0.1%+3mA
- Load stability : ≤0.2%+3mA - Ripple and noise: ≤2mArms ( effective value )
- Voltage Display Precision 3 digit LED display: ±1%±1 word
- Current Display Precision 3 digit LED display: ±1%±1 word
- Dimensions: 260x150x160 (mm)
- Weight : 6Kg.
16

.
Avometer
: اسماخ
UNI-T UT58A
: لولأا عونلا
17

18

: ىناثلا عونلا
UNI-T UT603
Modern Inductance Capacitance Meters
19

20

Multimeter : اسداس
MT 8045 BENCH TYPE DIGITAL MULTIMETER OPERATION MANUAL
21

1 ． LCD 2 ． Power switch 3 ． Function knob 4 ． VΩHz input terminal 5 ． COM
6 ． Less than 2A current input terminal
7 ． 20A current input terminal 8 ． Backlight switch 9 ． Hold switch
10 ． AC+DC measuring switch 11 ． hFE plug
12 ． Capacitance measuring plug 13 ． Bracket
14 ． 110V/220V transfer switch 15 ． fuse
16.Power plug
22

.
Function Generator
: لاوأ
. ةقدب ددرتلا ةميقل لوصولل Fine لا رز مادختسا و
.
.
مادختسلاا دنع لاا Power
HZ , KHZ , MHZ لاب ءاوس
Sine , Square or Triangle
لا رز ليغشت مدع
HZ Range طبض
: ةجوملا عون ديدحت
.
Oscilloscope
لا زاهج للاخ نم
. ابلاغ
Amplitude
لا ميق نم دكأتلا
Output
لا ىلع
Probe
لا مادختسا
.
Oscilloscope : ايناث
-
-
-
-
-
.
.
نكمم تقو لقأبو تلوف
ةجوملا تيبثتل
Stop
24
. ةيانعب
لا زواجتت ميقب
Prope
لا مادختسا ىلع ظافحلا
R.M.S Voltage
لا رزو ةقباسلا جئاتنلا عم لخادتلا مدعل
Auto
لاخدا مدع
لا رز مادختسا
.
Vertical or Horizontal ءاوس Scale بسانملا Position لاو Scale لا ديدحت
.
Analog / Digital Training System : اثلاث
-
-
-
-
.
Component
. ددرتلاو ةميقلا و ةجوملا عون طبظل
لكل
Function Generator
.
Pins
لا ىف صرحب كلاسلأا مادختسا
Data Sheet
لل اعبت ةبسانملا دوهجلا مادختسا
ك همادختسا دنع ةهجوملا تاميلعتلا سفن
-
-
-
.
.
DC Power Supply
: اعبار
بلاغلا ىف ىضرلااو بجوملا ىلع كلس فل مث نمو ةبسانملا تارايتلاو دوهجلا ميق ديدحت -
امبر سايقلا ةدحو ديدحت عم ةمواقملا وأ ةعسلا ،ددرتلا، رايتلا
.
Multimeter وأ Avometer : اسماخ
، AC or DC ءاوس دهج نم دارملا سايقلا عون ديدحت -
.وليكلاب امبر وأ وركيملا ، ونانلاب نوكت
Experiment No. (1)
Verifying Ohm's Law
Objective
23


To prove that the relationship between the voltage E and the current I in a D.C electrical circuit is linear.

To show that the slope of each relation equal the circuit resistance.
Theory
Ohm’s law states that at a constant temperature, current ' I' through a conductor between two points is directly proportional to the potential difference or voltage ' V' , across the two points. That is,
Thus, the ratio V: I is a constant. This constant is called as the resistance ( R ) of the conductor.
Resistance:


Resistance is the property of a component which restricts the flow of electric current. Energy is used up as the voltage across the component drives the current through it and this energy appears as heat in the component.
Resistance is measured in ohms, the symbol for ohm is an omega (Ω).
Resistors connected in Series: When resistors are connected in series their combined resistance is equal to sum of their individual resistances. For example if resistors R1 and R2 are connected in series their combined resistance, R , is given by:
Resistors connected in Parallel: When resistors are connected in parallel their combined resistance is less than any of the individual resistances. Equation for the combined resistance R of 2 resistors R1 and R2 connected in parallel is given by:
OR
Apparatus

E Stabilized DC Power Supply Unit.

V D.C Voltmeter.
24


A D.C Ammeter.

R Unknown Resistance.
Procedure
1.
Wire the circuit shown above ( Figure. 1 ) paying special attention to the polarity of instruments and to power supply unit E (that has be to off)
2.
Make sure that the ammeter has a range of 15 mA and the voltmeter has a range of 15 V.
3.
Set the power supply unit for a zero output voltage.
4.
True the power supply unit on.
5.
Adjust the power supply unit so that the E voltage values shown in the measurement table are obtained and not the corresponding I values.
6.
Switch off the voltage source.
7.
Plot a graph of E versus I for the data table (assign E for the vertical axis and I for the horizontal axis).
8.
Construct a right triangle on the graph, and form this, determine the slop and hence the resistance R .
9.
Evaluate the conductance G as G = I/R .
10.
Perform the calculation R = E /I shown in the third column of the measurement table and plot it against the current I .
11.
Compare the value of R obtained from (8) and that obtained from (10).
Figure 1 : Series RLC circuit.
Results
1. Make a graph of the ratio Vmax, R / Vmax vs angular, and ω.
25

2. Determine the resonance frequency fο, from the resonance curve and calculate LC using Eq. 3. How well does it agree with the value calculated from your best values for C and L?
Experiment No. (2)
Resistance Connected in Series and in Parallel
26

Objective
To deduce experimentally the relationship between two or more resistance in series or in parallel and to check the operation of the resulting voltage (resistance in series) or current (resistance in parallel) divider.
Theory
Resistors are probably the most commonly occurring components in electronic circuits. Practical circuits often contain very complicated combinations of resistors. It is, therefore, useful to have a set of rules for finding the equivalent resistance of some general arrangement of resistors. It turns out that we can always find the equivalent resistance by repeated application of two simple rules. These rules relate to resistors connected in series and in parallel.
Figure 2.1: Two resistors connected in series.
Consider two resistors connected in series , as shown in Figure 2.1
. It is clear that the same current flows through both resistors. For, if this were not the case, charge would build up in one or other of the resistors, which would not correspond to a steady-state situation (thus violating the fundamental assumption of this section). Suppose that the potential drop from point to point is . This drop is the sum of the potential drops V
1
and V
2
across the two resistors R
1
and R
2
, respectively. Thus,
2.1
According to Ohm's law, the equivalent resistance between and is the ratio of the potential drop across these points and the current which flows between them. Thus,
2.2
Giving
Here, we have made use of the fact that the current is common to all three resistors. Hence, the rule is
The equivalent resistance of two resistors connected in series is the sum of the individual resistances.
2.3
27

Figure 2.2: Two resistors connected in parallel.
Consider two resistors connected in parallel, as shown in Figure 2.2
. It is clear, from the figure, that the potential drop across the two resistors is the same. In general, however, the currents I
1
and I
2
which flow through resistors R
1
and R
2
, respectively, are different. According to Ohm's law, the equivalent resistance Req between and is the ratio of the potential drop across these points and the current which flows between them. This current must equal the sum of the currents I
1
and I
2
flowing through the two resistors, otherwise charge would build up at one or both of the junctions in the circuit. Thus,
2.4
It follows that
2.5
Giving
2.6
Apparatus

E Stabilized power supply unit.

V

A
D.C voltmeter.
D.C ammeter.

R
1
Resistance (1).

R
2
Resistance (2).
28

Procedure
A) Series Connection
1.
Wire the circuit shown in Fig 2-1 (for series connection).
2.
Set the power supply unit for a 12 V e.m.f.
3.
Measure the current I flowing through R
1
& R
2 and write its value in Table A.
4.
Measure the voltage V
1
across R
1
and V
2
across R
2
and write their values in Table A.
5.
Turn the power supply unit off.
6.
Perform the calculation shown below Table 2.1, and discuss the results.
Table 2.1
Series Connection
E =
I s
=
V
1
=
V
2
=

Applying to Ohm's law the circuit we get:
R s
= E / I = (V1+V
2
) / I
2
= V
1
/ I s
+ V
2
/ I s
.
But the total resistance of the circuit is given by R s
= R
1
+ R
2

Check the result obtained by the two formulas and discusses them.

B) Parallel Connection
1.
Wire the circuit shown in Fig 2-2 (for parallel connection).
2.
Set the power supply unit for a 12 V e.m.f.
3.
Measure the output current I1, from the power supply unit and note it in Table B.
4.
Unconnected R2 and measure, accordingly, the current I
1
, flowing through R1, note the current in Table
B.
5.
Unconnected R
1
and measure, accordingly, the current I
2 flowing through R
2
, note the current in Table
B.
6.
Turn the power supply unit off and unwire the circuit.
7.
Perform the calculations shown below Table B and discuss the results.
29

8.
Discuss the influence on the measurements due to the instruments connected in the circuit.

Applying to Ohm's law the circuit we get R p
= E / I

But the total resistance of the circuit is given by:
R p

1 / R
1
1

1 / R
2

R
R
1
1

R
2
R
2

Check the result obtained by the two formulas and discuss them.
Results
1. Make a graph of the ratio Vmax, R / Vmax vs angular, and ω.
2. Determine the resonance frequency fο, from the resonance curve and calculate LC using Eq. 3. How well does it agree with the value calculated from your best values for C and L?
30

Experiment No. (3)
Measuring the self-inductance of a coil
Objective

To measure the self-inductance and the resistance of a given coil.
Theory
A change in the magnetic flux threading a circuit is sometimes caused by a change in the current flowing in the circuit itself. In this case the e.m.f is said to be self-induced. If the circuit contains a coil of wire then the effect may be quite significant. An increasing current in the coil causes a back e.m.f to be induced that opposes the increase in the current. A decreasing current causes a forward e.m.f to be induced that resists the decrease in the current.
The magnitude of the induced e.m.f depends on a number of factors including the geometry of the circuit. The self-inductance, L, of a circuit is defined as
Where F is the total flux linkage through the circuit when the current is I. When a circuit comprises a single coil together with simple resistance, and a power supply as in this experiment, the coil is responsible for almost all the self-inductance in the circuit. In this case the value of L is characteristic of the coil itself and is called the self-inductance of the coil.
Apparatus

E Stabilized power supply unit;

V1 DC Voltmeter,

V2 AC Voltmeter;

A1 DC Ammeter;

A2 AC Ammeter;

V AC supply 220 V, 50 Hz,

L
1
Variac.
Procedure
1Wire the circuit as shown in Figure 3.1
.
2Set E for zero output voltage.
3Turn the power supply unit on.
4Record the ammeter and voltmeter reading in Table 3.
31

5Repeat steps (3&4), and draw the relation between V
1
& I
1
.
6From the graph, find the value of r, r =V
1
/ I
1
7Wire the circuit as shown in Figure 3.2
, and repeat the steps (2-5).
8Find the inductive impedance Z, Z
I
=V
2
/ I
2
9Find the self-inductance L using the relations
Z 1

Z 1
2
R


R
2 j

L

R 2
 
2
L
2
 
2 L 2
L

( Z 1
2

R
2
) /

2
ω=2 π f where f = 50 Hz
Figure 3.1 Figure 3.2
32

Results
V
1
DC
I
1
Table 3
33
V
2
AC
I
2

Experiment No. (4)
Measuring the capacitance of a capacitor
Objective

To measure capacitor resistance r.

To measure capacitor capacitance C.
Theory
The capacitance ( C ) of a capacitor can be found by charging it with a power supply and allowing it to discharge through a resistor of known resistance ( R ).
From theory the voltage across the plates of the capacitor as it discharges is given by
Where V
0 is the voltage at t = 0 . If the voltage across the plates of the capacitor is monitored while it discharges and an exponential curve is fitted to the resulting V vs t plot, the capacitance of the capacitor can be determined.
As the current I at any time t = ⅆQ ⅆt
where Q is the charge released by a capacitor from time t
1 to t
2
.
Apparatus

E Stabilized power supply unit;

V1 DC Voltmeter,

V2 AC Voltmeter;

A1 DC Ammeter;

A2 AC Ammeter;

V AC supply 220 V, 50 Hz,

L
1
Variac.
Procedure
1Wire the circuit as shown in Figure 4.1
.
2Set E for zero output voltage.
3Turn the power supply unit on.
4Record the ammeter and voltmeter reading in Table 4 .
5Repeat steps (3&4), and draw the relation between V
1
& I
1
.
34

6From the graph, find the value of r, r =V
1
/ I
1
7Wire the circuit as shown in Fig 4.2, and repeat the steps (2-5).
8Find the inductive impedance Z, Z
I
=V
2
/ I
2
9Find the capacitance C using the relations:
Z 1

R

1 j

C

R
2 
1

2
C
2
Z 1
2 
R
2 
1 /

2
C
2
C


Z 1
1
2

R
2
ω=2 π f
f = 50 Hz
Figure 4.2
: RC circuit.
Results
Plot the V out and compare it with V in at different values of resistances and capacitors.
35

Experiment No. (5)
Kirchhoff’s Voltage and Current Laws
Objective

To study Kirchhoff’s Current Law (KCL) and Kirchhoff’s Voltage Law (KVL) and their application in circuit analysis.
Theory
Kirchhoff’s Current law can be stated in words as the sum of all currents flowing into a node is zero. Or conversely, the sum of all currents leaving a node must be zero. Current flows through wires much like water flows through pipes. If you have a definite amount of water entering a closed pipe system, the amount of water that enters the system must equal the amount of water that exists the system. The number of branching pipes does not change the net volume of water (or current in our case) in the system.
Kirchhoff’s voltage law can be stated in words as the sum of all voltage drops and rises in a closed loop equals zero. As the image below demonstrates, loop 1 and loop 2 are both closed loops within the circuit. The sum of all voltage drops and rises around loop 1 equals zero, and the sum of all voltage drops and rises in loop 2 must also equal zero. A closed loop can be defined as any path in which the originating point in the loop is also the ending point for the loop. No matter how the loop is defined or drawn, the sum of the voltages in the loop must be zero.
Apparatus

Multimeter

DC power supply

Different Standard Resistors (as shown in Figure. 5.1 and Figure. 5.2
)
Pre-Lab Preparation
In this experiment we will study current and voltage relations in simple networks resulting from the interconnection of two or more simple circuit elements. The elements are assumed to be connected by perfect electrical conductors (zero resistance).
Figure. 5.1 Figure. 5.2
36

For the circuit of Figure. 5.1
and Figure. 5.2
write the simultaneous equations using Kirchhoff’s Laws and solve for the node voltages and mesh currents.
Procedure
1.
Connect circuit of Fig. 5-1 and measure all node voltages, and branch currents.
2.
Connect circuit of Fig. 5-2 and measure all node voltages, and branch currents.
Results
1.
Compare Table.5
the measured voltages and currents with the predicted values from the prelab.
2.
Explain any major discrepancies between the two sets of values. What are the advantages and disadvantages of each method?
Table.5
KCL KVL node
I I total
V I total
37

Experiment (6)
Verifying the Principle of Superposition
Objective

To verify the principle of superposition the electric network.
Theory
Superposition Theorem states that a circuit can be analyzed with only one source of power at a time, the corresponding component voltages and currents algebraically added to find out what they’ll do with all power sources in effect. To negate all but one power source for analysis, replace any source of voltage (batteries) with a wire; replace any current source with an open (break). In this practical we will learn to verify the
Superposition Theorem.
Apparatus

E
1
Stabilized power supply, 12 V, 50 mA.

E
2
Stabilized power supply, 6V, 50 mA.

A D.C ammeter.

R
1
Resistance (1) = 220 ohm.

R
2
Resistance (2) = 470 ohm

R
3
Resistance (3) = 330 ohm.
Procedure
1.
Wire the circuit shown in Figure. 6 .
2.
Feed it (E
1
= 10, E
2
= 5V) and read the value I of the current flowing in branch CD.
3.
Switch the voltage off, disconnect E
2
and replace it with short-circuit.
4.
Feed the circuit and read the I
1
current flowing in branch CD.
5.
Switch the voltage off, reconnect E2 and disconnect E
1
, replace it with short-circuit.
6.
Feed the circuit and read the I
2
current flowing in branch CD.
7.
Calculate the summation of I
1
and I
2
8.
The principle of superposition states that the value of I
1
+ I
2
is equal to the value of I.
9.
Check that your measurements verify the principle of superposition.
38

Figure. 6
Results
Repeat the experiment for different values of the circuit elements and write the results in the following table.
I
1
I
2
I Notes
39

Experiment (7)
Verifying the Reciprocity Theorem
Objective

To verify the reciprocity theorem in the electric networks.
Theory
Reciprocity Theorem states that – In any branch of a network or circuit, the current due to a single source of voltage (V) in the network is equal to the current through that branch in which the source was originally placed when the source is again put in the branch in which the current was originally obtained. This theorem is used in the bilateral linear network which consists bilateral components. As shown in Figure.7
, the various resistances R1, R2, R3 is connected in the circuit diagram above with a voltage source (V) and a current source (I). It is clear from the figure above that the voltage source and current sources are interchanged for solving the network with the help of Reciprocity Theorem.
Figure.7
Apparatus

E
1
Stabilized power supply, 12 V, 50 mA.

A D.C ammeter.

R
1
Resistance (1) = 220 ohm.

R
2
Resistance (2) = 470 ohm

R
3
Resistance (3) = 330 ohm.
Procedure
1.
Wire the circuit as shown in Figure. 7. (the wires in solid lines)
2.
Feed the AB points through the 12 V-power supply while the ammeter is connected through CD.
3.
Measure the current I
1
flowing in branch CD.
4.
Connect the power supply between the CD points and the ammeter between the AB points.
40

5.
Measure the current I
2
flowing between A and B.
6.
Compare I
1
and I
2
7.
The reciprocity theorem states that they two currents have the same value.
8.
Check that your measurements verify the reciprocity theorem.
9.
Repeat the experiment for different values of the circuit elements and write the results in the following table.
Results
Repeat the experiment for different values of the circuit elements and write the results in the following table.
I
1
I
2
Notes
41

Experiment No. (8)
Verifying Thevenin's Theorem
Objective

To verify Thevenin's theorem in a simple D.C circuit.
Theory
A linear network consisting of a number of voltage sources and resistances can be replaced by an equivalent network having a single voltage source called Thevenin’s voltage (V
Th
Thevenin’s resistance (R
Th
) and a single resistance called
). Thevenin’s Theorem makes this easy by temporarily removing the load resistance from the original circuit and reducing what’s left to an equivalent circuit composed of a single voltage source and series resistance. The load resistance can then be re-connected to this “Thevenin equivalent circuit” and calculations carried out as if the whole network were nothing but a simple series circuit:
Figure 8.1: Linear Circuit.
Figure 8.2: Thevenin Equivalent Circuit.
42

Apparatus

E

V

A

R
Stabilized power supply unit.
D.C voltmeter.
D.C ammeter.
Resistances (R
1
, R
2
, R
3
).
Procedure
1. Measure the supply voltage and resistance of each resistor. Record these values in Table 8.1. Select R
L
as the resistor where it is proposed to determine the current value.
2. Construct the circuit in Figure 8.3. Do not turn on the supply.
3. Remove resistor R
L
from the network.
4. Turn on the supply. Measure the voltage between the points A and D of the network. This is the Thevenin’s voltage. Record the value in Table 8.1.
5. Switch off the power supply. Replace the power supply V1 with a short circuit.
6. Measure the resistance between terminals A and D. This is the Thevenin’s resistance. Record the value in
Table 8.1.
7. Place back the resistor R
L
in circuit with an ammeter is connected between terminals A and B or C and D.
8. Remove the short circuit connection and place back the supply in the circuit.
9. Turn on the supply. Read and record the current value flowing in the resistor R
L
.
10. Draw Thevenin’s equivalent circuit inclusive of resistor R
L
.
Figure 9.3: Simple D.C circuit.
43

Results
Table 8 :
Norton’s Theorem
Measured values
Thevenin’s resistance
Thevenin’s voltage
Current in
R
L
Thevenin’s resistance
Theoretical values
Thevenin’s voltage
Current in
R
L
44

Experiment No. (9)
Verifying Norton’s Theorem
Objective

To verify Norton’s theorem in a simple D.C circuit.
Theorem
Norton’s Theorem states that it is possible to simplify any linear circuit, no matter how complex, to an equivalent circuit with just a single current source and parallel resistance connected to a load. Just as with
Thevenin’s Theorem, the qualification of “linear” is identical to that found in the Superposition Theorem: all underlying equations must be linear (no exponents or roots).
Figure 9.1: Linear Circuit.
Figure 9.2: Norton Equivalent Circuit.
As with Thevenin’s Theorem, everything in the original circuit except the load resistance has been reduced to an equivalent circuit that is simpler to analyze. Also similar to Thevenin’s Theorem are the steps used in
Norton’s Theorem to calculate the Norton source current (I
Norton
) and Norton resistance (R
Norton
).
Apparatus

E

V

A

R
Stabilized power supply unit.
D.C voltmeter.
D.C ammeter.
Resistances (R
1
, R2, R3).
45

Procedure
1Construct the circuit as shown in Figure 9.3. Do not turn on the supply.
2Remove resistor R
L=
R
2
from the network. R
L=
R
2
is selected as the resistor where it is proposed to determine the current value.
3Turn on the supply. Read the current shown by the ammeter between terminals A and D. This is
Norton’s current, I
N
. Record its value in Table 9.1.
4Switch off the power supply. Replace the supply with a short circuit.
5-
Measure the resistance between terminals A and D. This is Norton’s resistance, record the value in Table
9.1.
6Place back the resistance R
2
in circuit with an ammeter is connected between terminals A and B or C and D.
7Place back the power supply in the circuit and remove the short circuit connection.
8Read and record the current value flowing in the resistor R
2
.
9-
Draw Norton’s equivalent circuit inclusive of resistor R
2
.
Figure 9.3: Simple D.C circuit.
46

Results
Table 9 :
Norton’s Theorem
Norton’s
Resistance
Measured values
Norton’s current
Current in
R
L
Norton’s
Resistance
Theoretical values
Norton’s current
Current in
R
L
47